This project develop a clinical monitoring system to quantify blood flow (perfusion) continuously, in real-time, using non-invasive senors. Perfusion quantification is now effectively unavailable, yet insuring adequate tissue blood flow is universally acknowledged as being essential to many medical procedures. Examples include reconstructive surgery, organ transplantation, vessel grafting, bypass procedures, and burn and wound healing, each of which depends on a viable vasculature. The perfusion monitoring system will ultimately comprise and array of multiple non-invasive surface sensors and translation electronics under control of a personal computer which also provides the user interface, data collection and management software. This Phase I project addresses the feasibility and optimal design of the non-invasive perfusion sensor. Prototype senors will be fabricated and evaluated, a thermal model of the sensor will be formulated to extract perfusion from raw power versus time data and preliminary validation studies will characterize sensor sensitivity, response and accuracy. In Phase II, the non-invasive sensor design will be replicated to a sensor array designed to provide a map of the tissue perfusion distribution. Applications will be to numerous medical procedures whose success depends on restoring and maintaining a viable tissue vasculature and to the identification of ischemic tissue leading to diagnosis and early options for management of treatment. PROPOSED COMMERCIAL APPLICATION Many of the 500,000 muscle and myocutaneous flap reconstructions, 12,000 kidney and 4,000 liver transplants performed in the US each year as well as other procedures whose success depends on restoring and maintaining a viable tissue vasculature could greatly benefit from this proposed device that will non-invasively quantify tissue perfusion continuously and in real-time. Current competing techniques to measure tissue flow are either extremely complex and performed only in the context of physiologic research or are too simplistic to yield useful information in terms of the flow level, variation, quantification and spatial distribution.